This is a creative first for me as I have never used a lathe before this project. It is also the first time that I've tried to make a truly precise thing - where it mattered if things were a little off the design. I'm normally I'm a 'slap it together' kind of person, so this was a big challenge for me.

I wanted to make the ultimate toy for my nephew's first birthday, and (if I say so myself) this was the perfect project.

It takes a fair bit of time, but it is certainly worth it. It's also a great project for practicing skills on, because you need to make 12 of the same shape on the lathe.

The idea for this project came from an old Ikea toy that my friend had - I used it as the model to create this toy. Even with the example, there was LOTS of prototyping and figuring things out.

Step 1: Tools and Materials

Materials:

2 foot long, 2 by 6 inch birch (or other hardwood) board.
NOTE: I chose a hardwood because the point of this toy is to be dropped. Using a softer wood would result in denting and damage to the toy.
12 3/8" Rare earth magnet, cup and washer sets. I ordered these from Lee Valley.
Sandpaper - from 60 grid to 220 grid.
Milk paint or other baby safe option.
Finish - I used beeswax salad bowl finish for a baby-safe option.
Wood filler

Tools:

Compass tool (for drawing circles).
Square and ruler.
Chop saw and band saw.
Wood lathe.
Set of lathe gouges - I used 3 sizes. It is also really good to have a sharpening system (like a Tormek) handy as turning hardwood is hard on your tools. I sharpened my gouges between each piece.
Drill press
Forstner bit the same size as your magnets.
2-inch hole saw bit.
Drill or screwdriver.
Disc sander.

You'll likely want some safety equipment like safety glasses and a dust mask.

Step 2: Preparation

First, cut the blocks that you will shape into the pieces of your final product.

Using a table saw, cut the birchwood in half lengthwise so that you have two 3-inch wide pieces.
Using a chop saw or a band saw, cut 13 square blocks that are 3 x 3 inches.
Find the centre of each block by drawing lines corner to corner and mark it on both sides.
I drew a 3x3 inch circle on 12 of the blocks (photo 1) and used a band saw to get rid of the edges. These are the pieces that I put into the lathe. If you have a 3-inch hole saw (I didn't), I would consider using it to cut all of these out because it will save you some roughing time on the lathe.
Using the 2 inch hole saw, cut out the cylinder you will use for the centre piece (photo 2).

Now, make the cardboard template that you will use to try to ensure that all of your pieces on the lathe are the same (photo 3)

Draw a triangle that is 3.5cm at the base, and goes to the edge of the cardboard.
Mark a spot 1cm above the base of the triangle on the edge of the cardboard. draw a slight curve from the edge of the triangle to meet that point.
Cut out the template.

I also cut out a pentagon with 2cm sides to help me in my next step.

Step 3: The Centre Piece

This part took me a whole lot of time and prototypes to figure out. When I finally figured out that I had to start with a cylinder rather than a block, it changed everything! The last photo shows one of my prototypes.

The following steps are what I came up with as the easiest method for creating the centre piece.

Take your 2 inch cylinder and draw a mid-line around the circumference of the block.
Draw a pentagon on one of the sides of the cylinder. I used the template I made in the previous step for this.
Find the centre of each of the sides of the pentagon and draw a perpendicular line out from that point to the edge of the block, and then down the entire side of the block. When you reach the edge of the opposite side of the block, continue the line in a little bit. This will be where the the point of the second pentagon will be.
Draw the second pentagon on the opposite side of the block. Because of the lines you drew in the previous step, the pentagon will be exactly offset the first pentagon.
Now, here comes the hard part. Using a disk sander with 60 grid sandpaper, sand down to the edge of each of the pentagon sides and the midline of the cylinder. Try to ensure that you get a flat plane between the midline and each side of the pentagon. Do this for each of the sides. Photo 2 shows this process half complete and photo 3 shows me starting out the other side. You can see in photo 3 that I lined up the edge of the pentagon by eye and started sanding - correcting if I needed to.
When you sand down to the centre line on each side- there will be a small strip around the middle that you didn't touch - that's supposed to be like that, you don't have to sand until all of the edges of all of the sides touch or it won't line up properly.
Check your work on each of the sides - the opposite sides should all be parallel to one another. Correct any of the planes that didn't come out correctly. As you see in photo 4, this side isn't level so I corrected it by sanding the high sides until I checked and it was level. This takes a long time, but it is important that you spend the time and do it correctly or else your outer pieces won't fit together very well.

Step 4: The Outer Pieces

The same steps will apply to all of the 12 pieces.

As I mentioned, this was my first time using a lathe. I did a bit of reading to learn some techniques and got a couple of demos from a friend at YuKonstruct. I used a scrap piece of wood to try this out the first few times - and then applied what I learned the the other pieces. I found it helpful to use three different gauges, and sharpening them between each piece was pretty essential.

Place one of the blocks into your wood lathe - make sure to line up your centre marks with the lathe so that the cylinder is straight and in place.
Rough out the piece so that it is even and round;
Create the angle. On mine, I found that the edge of the tool post to the diameter of the circle made the correct angle. As you are going, check every once in awhile against your template to see if you are getting the right slant (photo 1).
Once you have the angle, shape the top edge.
Your starting diameter is 3 inches. Rounding the top edge down makes your final diameter closer to 2.5 inches. You only want to bring the edge down about a centimeter (like your template). Use a set of calipers to make sure that you are ending up with the same diameter for each piece. If it is too big around, but you already rounded the top down 1cm, then bring your whole angle in a bit. Stop once you match the template and you are happy with the diameter.
Sand. sand sand sand - starting with 60 grit and working your way to 220. I sanded the pieces while they were still on the lathe and finished them off by hand.

Repeat for all 12 pieces!

Step 5: Checking the Fit

It is good to check if your toy will come together at this point. I used some sticky tack to hold all of the pieces in place before adding the magnets. I didn't have to re-cut any of the pieces, but I made some more adjustments to the centre piece - sanding high edges down so that all of the outer pieces fit really well together.

Another adjustment that I made at this stage was to sand all of the bases of the 12 outer pieces about 1/4 inch. This made their bases a bit bigger round to make the pieces fit a bit closer together. This is not essential and it will depend on how well and tight your ball fits together. You want it to be ball-shaped, so the pieces can't be too far apart, but having a bit of space between the pieces helps your child pick up the toy.

Step 6: Magnets and Finishing Pieces

Using the forstner bit, drill a hole the exact size and depth of your magnet in every side of the centre piece (photo 1).
Hand sand the entire centre getting rid of the sharp edges (start with 60 and work your way to 220 grit).
Screw in the 'cup' magnet piece onto each of the 12 outer pieces. Use epoxy to glue in the magnet that fits into the cut, as you don't want any chance of this falling out.
Screw the washer magnet piece into each of the holes you made into your centre piece. Because of the pilot from your hole saw, there will be two holes where it is impossible to screw into the wood. Just use epoxy to glue the pieces in here.
Using a bit of wood filler, I filled the small hole that the lathe made in my outer pieces. Let it dry, and then sanded it down again.

Step 7: Nearly There!

At this stage I took a bit of a break and glorified in my success - the ball fit together! There were many points when I didn't think it would work out.

To check if it would withstand being played with, I asked my friend's baby to check it out. Luckily, I got the stamp of approval!

Step 8: Paint

I used three different colours of milk paint and applied them with a make-up sponge. I could have done two coats for an opaque finish, but I wanted to see a bit of the wood coming through. I also decided only to paint the tops, leaving the sides to show the wood grain.

After the paint was dry, I used beeswax salad bowl finish over the entire surface of every piece (including the centre).

Step 9: The End.

Smashing is clearly the best part of this toy - but putting it back together is also fun and it helps with fine motor skills.

My nephew also came up with this hilarious 'Strong Man' game where he stuck the magnets of two of the pieces together, pulled them apart, and then showed off his muscles.

My cousin's kids who are much older also have fun with this toy. Trying to make patterns with the placement of the pieces was one fun activity, and bowling with it was another hit.

What did I learn? Besides the ability to use the lathe, I learned the power of prototyping. Even though it took some time, it was great to rough out and test how things would work out with scrap pieces of wood. This saved me a whole lot of mistakes when using my more expensive hardwood and was especially important for this project as small mistakes made a big difference in how the project fit together.

I wasn't sure I had it in me to take on such a detail-oriented project, and I am really proud of how this turned out.